As Earth’s climate becomes warmer, sleepless nights will increase for many, predicts a study from the University of California, San Diego. The research links sleep data on 765,000 Americans collected by the U.S. Centers for Disease Control and Prevention with climate models that predict warming trends. Rising temperatures could cause six additional nights of poor sleep per 100 people by 2050 and 14 by 2099. Seniors, which have difficulty regulating body temperature, and low-income people without air conditioning, are likely to be the most affected.